System for steering a casting belt in a continuous metal casting machine of the drum and belt type



I tamed States Patent 172] lnventors Robert William Hazelett;

Richard Ilazelett, Malletts, Bay. Vermont [21} Appl. No. 754.056

122 Filed Aug. 20, 1968 145] Patented Oct. 13,1970

[731 Assignee Hazelett Strip-Casting Corporationt Malletts Bay,Winooski.Vermont [54] SYSTEM FOR STEERING A CASTING BELT IN A CONTINUOUS METALCASTING MACHINE OF 3,336,972 8/1967 Coferet a1 164/2725 PrimaryExaminer-J. Spencer Overholser Air/slum Examiner-R. Spencer Annear:lllOlHQY-RODBI'ISOU, Bryan. Parmelee and Johnson ABSTRACT: System forsteering a casting belt in a continuous metal casting machine of thedrum and belt type. herein described. wherein a continuously moving moldspace is defined between the periphery of a revolving drum and anendless belt which envelopes approximately half the circumference of thedrum. ldler wheels apply tension and provide guidance and support forthe casting belt. This invention ena bles steering an advantageouslythin casting belt in proper alignment on flangeless wheels while at thesame time applying adequate tension to the casting belt to preventleakages of the molten material being cast. This invention enables verythin casting belts to be used which yields the advantages of moreeffective cooling, less belt distortion, longer belt life. and longerlife of the casting drum and a more uniformly cooled quality castproduct. In the illustrative embodiment the steering is accomplished bytwisting the axis of the exit pulley wheel about a pivot P positionednear the inside or rear edge of the casting belt, the pivot axis lyingapproximately in the same plane as the tangent point at which the beltcoming from the rim of the casting drum contacts the exit wheel. thus.maintaining the thin belt centered on flat, flangeless, contact surfacesofthe pulley wheels.

Patented Oct. 13,1970

Sheet of 2 INVENTORS. Q m 1921562??? BY 34.671072? M56262? NORA/5Y5,

Roller? Wilda m 3? v v:

Patented Oct. 13, 1970 3,533,46

Sheet 2 012 SYSTEM FOR STEERING A CASTING BELT IN A CONTINUOUS METALCASTING MACHINE OF THE DRUM AND BELT TYPE In a continuous metal castingmachine of the drum and belt type such as described herein prior to thisinvention, the casting belt has been guided by flanges on the outsideedges of the respective idler wheels and/or casting drum. However, thisarrangement has experienced a great many difficulties for many years andhas restricted the commercial usages of this drum and belt type machine.The flanges cause considerable wear and buckling of the edges of thebelt which damages the rim of the casting drum. The casting belt must beflat and held firmly against the rim of the casting drum to preventleakage of the molten metal.

In drum and belt type casting machines it is desirable to use a beltwhich is thin because the belt is flexed in one direction when it passesaround the casting drum and then it flexes in the opposite directionwhen it passes around the three idler wheels. The belt is revolvingcontinuously, and therefore it is repeatedly flexed in one direction andthen in the other, therefore, the flexural stresses would be reduced andthe belt life greatly extended by using a thin belt. However, because ofthe necessity in the prior art to use flanges to steer the casting belt,it has been necessary to use a thicker casting belt. When attempts havebeen made in the prior art to use a thin belt under adequate belttension, it rapidly wears along its edges where they engage the flanges.It has a tendency to climb the flanges as it enters the wheels, thusdistorting, tearing or rolling over the edges of the belt. 7

In order to minimize these problems the prior art has used a relativelythick belt (over 0.060 of an inch). However, a thick belt interfereswith effective uniform cooling of the molten metal and is more expensivethan a thin belt. Also, a thick belt can soon fail from excessiveflexural stresses and heat distortion.

In view of these disadvantages of a thick belt, we prefer a thin belt ofa thickness of less than 0.060 of an inch. Among other reasons, weprefer a thin belt because we find that a relatively. thin belt can bemore effectively and uniformly cooled and so is the cast product; thereis less distortion of the belt, providing a more uniform qualityproduct, and the belt has a considerably longer life.

This problem of maintaining the casting belt evenly on uncrowned wheelswithout wear and damage to its edges, has remained unsolved for sometime and much effort and expense has been expended to find a way ofpreventing this rapid deterioration of the casting belt.

Accordingly, it is an object of this invention to provide apparatus forsteering the casting belt in proper alignmenton wheels having flat,cylindrical, uncrowned contact surfaces, without the use of flanges, andat the same time apply adequate tension to a thin belt without creatingleakages between the casting belt and the casting wheel.

In this specification and in the accompanying drawings are described andshown a continuous casting machine embodying the present invention, butit is to be understood that this illustrative example of a presentlypreferred embodiment is not intended to be exhaustive nor limiting ofthe present invention, but on the contrary is givenfor purposes ofillustration in order that others skilled in the art may fullyunderstand the invention and the manner of carrying out the invention inpractical use and so that they will understand how to utilizeequivalents of the elements shown as may be best suited to theconditions of various particular continuous casting installations.

The various features, aspects, and advantages of the present inventionwill be more fully understood from a consideration of the followingdescription in conjunction with the accompanying drawings, in which: i

FIG. 1 is a front elevational view of a casting machine of the drum andbelt type embodying the steering apparatus of the present invention;

FIG. 2 is a partial sectional plan view ofthe exit wheel ofthe castingmachine shown in FIG. 1, as seen from the direction 2-2 in FIG. landdrawn on a slightly enlarged scale;

FIG. 3 is an enlarged front elevational viewof the stand on which theexit wheel is mounted as seen at the upper left in FIG. 1; and

FIG. 4 is an enlarged side elevational view of the stand shown as seenfrom the direction 44 in FIG. 3, illustrating details of the steeringmechanism according to the present invention.

As shown in FIG. 1. the continuous casting machine 10 includes a framebase 12 having a casting drum 14 rotatably mounted on the base. Aflexible casting belt 16 runs in an arcuate path around approximatelyone-half of the circumference of the revolving drum 14 and is guided andsupported by three idler pulley wheels 17, 18, and 19. Between theperiphery of the revolving drum 14 and the casting belt 16 is defined amoving mold space 20 into which a molten material 22 is poured to becast. The molten material 22 is seen enter ing the machine by beingpoured downwardly on the right side of the drum in FIG. 1, and the castproduct 25 exits from the left side of the drum in an upward direction.

In order to contain the molten material 22 within the mold space 20 andto cast a product of high quality, it is important that the casting belt16 be held firmly against the flat rim surfaces of the casting drum 14and the unflanged contact surfaces of the pulley wheels 17, 18, and 19.That is, its front face F' must continue in a smooth curvature adjacentto the casting drum 14 and pulley wheels l7, l8, and 19 without anywarping or localized distortion. The rear face R of the belt 16 iscooled by a fast traveling liquid coolant 23, for example such as waterwhich may be used in this machine.

The belt 16 is cooled in the region where it encounters the downflowingmolten metal 22 by a liquid coolant 23 fed under high pressure through aline 24 into a manifold 26 which is connected to a plurality of nozzles27 which nest in grooves in the contact surface of the entrance wheel 17and curve approximately half way around this wheel. In its travel aroundthe casting drum 14, the belt 16 is cooled by means of a coolantsupplied to a header 28 extending in an arc concentric with the axis ofthe drum l4 and located near one edge of the belt 16. The coolant issupplied under pressure to the header 28 through a plurality of lines 32and is applied against the rear surface R" of the belt at an angle sothat the coolant impinges to spread out and form a fast travelling film(not shown) moving transversely across the face R". The header 28 ismade in three sections joined by flanges 30. The arcuate header 28 ismounted on the frame 12 by a plurality of supports 34. The, method andapparatus used for cooling the casting belt 16 is shown and described ingreater detail and is claimed in our copending application, Ser. No.542,566, filed Apr. 14, 1966, now US. Pat. No. 3,429,363, the disclosureof which is incorporated herein by reference.

As shown in FIG. 1, the molten material 22 is supplied from an insulatedpouring container or tundish 36 and feeds down through a spout 38 intothe input region or entrance 40 to the mold space 20. This machineisparticularly adapted for continuously casting molten metal, such asaluminum, steel and copper. The cast product 42 is led out of themachine at a point which is on the opposite side from the entrance 40,i.e., adjacent to the exit pulley wheel 18.

In following the path described by the casting belt 16 near the entrance40, it is seen that the rear face R" describes a concave curve as itturns around the entrance wheel 17; then the belt flexes through-areverse curve or line of inflection along a transverse line, and thenthe rear face R" describes a convex curve as it runs around the drum 14.After the belt has traveled approximately half way around thecircumference of the casting drum 14, it exits from the drum andreverses its flexure so as to describe a concave curve as it turnsaround the pulley 18 and then downward at an angle, then curving aroundpulley wheel 19 and back up at an angle to pulley wheel 17, as shown bythe arrows in FIG. 1. The converse of these directions of flexure occurwith respect to the front face F.

Referring also to FIGS. 2. 3 and 4, the steering apparatus of thepresent invention includes a stand 44, including an upper portion 46 anda lower portion 48, which is fastened to the frame base 12 of thecasting machine 10. The upper stand portion 46 is pivotally mounted onthe lower stand portion 48 by means of a pivot "P near the inside (rear)edge of the exit pulley 18, approximately in the plane of the tangentpoint of contact of the belt l6 with the drum 18.

As seen in FIG. 2 the contact surface of the exit pulley wheel 18 isflat without any flanges thereon and the belt I6 engages this contactsurface as it passes around the pulley wheel 18. The casting belt 16 issteered by twisting the axis of the exit pulley wheel 18 with respect tothe axis of the remaining pulley wheels 17 and 19. This twisting of theaxis of the exit wheel 18 is accomplished by turning the upper standportion 46 about the pivot "P as will be explained in detail furtherbelow.

The exit pulley wheel 18 is carried by a rotatable shaft 50 mounted ina-bearing member 52 secured to a plate 54 by a series of bolts 55. Theback end of the bearing member 52 is en closed in a housing 56, closedat the opposite end by a member 58 with a brace 60 holding the plate54in place.

As shown in FIGS. 1 and 2, there are a pair of eccentrics 62 and 64.Eccentric 62 is journaled in a bearing block 63 secured to the upperstand portion 46, and the eccentric 64 is journaled in a bearing block65 secured to the lower portion 48 of the stand 44. Specifically, thebearing block 63 is secured to a plate 70 forming the bottom of theupper stand portion 46, and the other bearing block 65 is secured to theside of the pedestal frame 49 of the lower stand portion 48. As can beseen, the eccentric 64 has a smaller eccentricity than eccentric 62. Thelarger eccentric 62 is used for initial adjustment to'center the castingbelt on the pulley wheels l7, l8, and 19, while eccentric 64 is forcontinuously steering the endless casting belt I6 on the flat contactsurfaces of the wheels.

In making the initial adjustment to center the casting belt, the maindrive (not shown) is placed in operation to rotate the casting drum 14,which causes the belt 16 to travel along its path as seen in FIG. 1passing around the drum and around the three idler wheels l7, l8 and 19.As the belt 16 is revolving a large wrench is used to turn the eccentric62 until the belt 16 is centered on the flangeless contact surfaces ofthe three pulley wheels. This adjustment is made while the othereccentric 64 is in the middle of its operating range. After the initialadjustment is completed, a lock screw 67 is tightened to hold theeccentric 62 in place. A similar lock screw 67 is provided to lock theother eccentric 64 temporarily during initial adjustment. During castingoperation the lower eccentric 64 is actuated by steering drive means 68shown as a handle lever. This handle lever 68 may be operated manuallyto steer the casting belt or the steering drive means 68 may be actuatedby a hydraulic cylinder and piston mechanism 69 having its piston rodpivotally connected at 71 to the lever 68, the cylinder being pivotallysecured at 73 to the pedestal frame 49. A sensing mechanism (not shown),such'as a switch having a finger lightly touchingthe edge of the belt16, serves to sense the position of the belt for automaticallycontrolling the cylinder 69. 1

Referring to FIGS. 2 to 4, it is seen that the eccentrics 62 and 64 areconnected by a link member 66 which engages eccentric portions of theeccentrics 62 and 64. By turning the eccentric 62 or 64, the bearingblock 63 is pulled by the link member 66 either toward or away from thebearing block 65.

When the bearing block 63 is pulled generally toward the bearing block65, then the upper stand portion 46 is turned in a clockwise direction C(FIG. 2) about the pivot P. This turning movement of the upper standportion twists the axis of the shaft 50 of the exit wheel 18 in aclockwise direction C with respect to the axes of the other pulleywheels and drum. When the bearing block 63 is pushed generally away fromthe bearing block 65, then the upper stand portion 46 and the axis ofthe shaft 50 is twisted in a counterclockwise direction D about thepivot P. As can be seen with this arrangement, the axis of the exitwheel 18 can be twisted in either direction with respect to the axes ofthe other pulleys and the drum and thereby cause the belt 16 to bedisplaced in either direction across the surfaces of pulleys l7 and 19to maintain the belt properly aligned on the wheels.

The angular movement C or D about the pivot P at which the axis 50 ofthe exit wheel 18 is twisted about the pivot P is approximately 1 ineither direction, 1.6., i: I", from the neutral position. The neutralposition is that in which the axis 50 of the wheel 18 is parallel withthe axes of the other wheels and drum. After the belt has been initiallycentered, the steering drive means 68 is operated from time to timewhenever the belt begins to creep forwardly or backwardly along thecontact surfaces of the wheels I7, 18 and 19. that is, whenever itbegins to deviate from its center position.

Twisting the axis 50 of the exit wheel 18 causes the belt to follow anew path as it revolves about approximately one-half of thecircumference of the wheel 18. This new path causes the belt to displaceitself, i.e., to creep slowly, in an axial direction along the contactfaces of the other pulley wheels, thus counteracting the deviation so asto return the belt to the center position. Twisting the axis 50 in aclockwise direction C" causes the belt 16 to displace slowly backwardly(away from the reader in FIG. 1). Conversely, twisting the axis 50 in acounterclockwise direction D" causes the belt to displace slowlyforwardly (toward the reader in FIG. 1).

As shown in FIGS. 2 to 4, the upper stand portion 46 and lower standportion 48 are arranged so the upper portion 46 slides over the lowerp0rtion 48. The upper portion 46, being mounted on a steel bearing plate70 which slides over a friction reducing porous bronze oil-impregnatedbearing plate 72 resting on top of a steel bearing plate 74 at the topof the pedestal frame 49. The thin friction reducing plate 72, such as abronze plate, is interposed between plates 70 and 74 to reduce thefriction between them when the upper portion 44 is being pivoted in thedirections C" or D".

In order to hold down the upper plate 70, to counteract the weight ofthe wheel 18 and shaft 50 and tension force of the belt 16 being exertedon it, a retainer strip 76 is provided which is secured at each end tothe lower plate 74 by means of bolts 78. As can be seen, the extent towhich the plate 70 can pivot in alternate directions is limited by thebolts 78.

It is noted that as an alternative the entrance or first pulley wheel 17may also be arranged to have its axis twisted, i.e., arranged like theexit pulley 18 and with this arrangement, the casting belt 16 could besteered. However, we prefer to use the exit wheel 18 in the steeringsystem because of the presence of the molten metal 22 at the entrance tothe casting machine.

In the casting machine as described the belt 16 has a thickness of lessthan 0.060 of an inch, and when incorporated in the system as describedit yields the many advantages described in the introduction as well asbeing less expensive and lasting much longer than those in the priorart, while producing a more uniformly cooled cast product.

The terms and expressions which we have employed are used in adescriptive and not in a limiting sense, and we have no intention ofexcluding such elements as are equivalents of the elements of theinvention described above and defined within the scope of the appendedclaims.

We claim:

1. A system for steering the casting belt in a continuous castingmachine of the revolving drum and belt type having an endlesscastingbelt which runs partially around a revolving drum and is guided andsupported by a plurality of pulley wheels and for extending the life ofthe belt comprising a casting belt having a thickness of less than 0.060of an inch, said belt having a front face F" engaging approximately onehalf of the circumference of the drum defining a casting mold betweenthe revolving drum and the'front face of the moving belt, said pluralityof pulley wheels having flangeless contact surfaces engaging the rearface R of the belt, frame means for the machine, said pulley wheelsbeing mounted on said frame means with their axes parallel with the axisof the drum, one of said pulley wheels being positioned near the drumfor guiding the casting belt with reference to the revolving drum. pivotmeans pivotally mounting said one pulley wheel, said pivot means havingan axis lying in a plane extending in a direction substantiallytangentially to the circumference of said one pulley wheel on the sidethereof toward the drum for twisting the axis of said one pulley wheelabout the axis of said pivot means, for steering the belt to keep itgenerally centered on the flangeless contact surfaces of said pulleywheels.

2. A system for steering the casting belt in a continuous castingmachine as claimed in claim 1 in which said one pulley wheel is the onewhich serves as the exit pulley wheel for receiving the casting beltafter it has traveled around the revolving drum, said pivot means beinglocated near the rear edge of the belt near the region where the beltfirst engages the flangeless contact surface of said exit pulley wheel.

3. A system for steering the casting belt in a continuous castingmachine as claimed in claim 1 including a stand for mounting said onepulley wheel, said stand having a lower portion secured to the framemeans of the machine, said stand having an upper portion, said pulleywheel being rotatably mounted upon said upper stand portion, said upperstand portion being slidably mounted upon said lower stand portion upona slide bearing whose plane extends parallel with the axis of saidpulley wheel, said pivot means pivotally interconnecting said upper andlower stand portions, and steering means for sliding said upper standportion relative to said lower stand portion while pivoting about saidpivot means.

4. A system for steering the casting belt in a continuous castingmachine as claimed in claim 3 in which said upper stand portion includesa base plate near said slide bearing, retainer means secured to saidlower stand portion at a position spaced from said pivot means, saidretainer means extending above a portion of said base plate for holdingsaid base plate down to stabilize said upper stand portion. saidretainer means providing clearance for said base plate to pivot alimited extent about said pivot means.

5. A system for steering the casting belt in a continuous castingmachine as claimed in claim 3, in which said steering means is adaptedto slide said upper stand portion about said pivot means though an angleof approximately i l relative to a neutral position.

6. A system for steering the casting belt in a continuous castingmachine of the revolving drum and belt type having an endless castingbelt which runs partially around a revolving drum and is guided andsupported by a plurality of pulley wheels comprising a casting belthaving a thickness of less than 0.060 of an inch, said belt having afront face F curving around a substantial portion of the circumferenceof the drum defining a casting mold between the revolving drum and thefront face of the curving belt, said plurality of pulley wheels havingflangeless contact surfaces engaging the rear face "R" of the belt,frame means for the machine, said pulley wheels being mounted on saidframe means with their axes parallel with the axis of the drum, one ofsaid pulley wheels being positioned near the drum and serving as theexit wheel for receiving the casting belt after it has traveled aroundthe revolving drum, pivot means pivotally mounting said exit pulleywheel, said pivot means being located adjacent the edge ofthe flangelessrim of said exit wheel and the circumference of the drum and steeringmeans for twisting the axis of said exit pulley wheel about the axis ofsaid pivot means, for steering the belt to keep it generally centered onthe flangeless surfaces of said pulley wheels.

7. A system for steering the casting belt in a continuous castingmachine of the revolving drum and belt type having an endless castingbelt which runs partially around the circumference of a revolving drumand is guided and supported by a plurality of pulley wheels, said systemcomprising a machine frame, a plurality of flangeless pulley wheelsmounted on said frame and having their axes parallel with the axis ofthe drum, a stand having an upper portion on which one of said pulleywheels is rotatably mounted. said upper portion being pivotallyconnected by pivot means to a lower portion of said stand, said lowerstand portion being fastened to said machine frame, said stand beinglocated near the circumference of said revolving drum, said pivot meansbeing positioned on the side of said stand near the circumference ofsaid drum and said one of said pulleys and the pivot axis of said pivotmeans lying in a plane extending in a direction generally aligned withthe direction of the adjacent portion of the belt, and steering meansfor moving said upper stand portion. back and forth about said pivotmeans for steering the belt to maintain it centered on said flangelesspulley wheels.

8. A system for steering the casting belt in a continuous castingmachine of the revolving drum and belt type as claimed in claim 7, inwhich said pivot means is located generally behind the rear edge of thecasting belt, when viewed from the front of the machine looking in adirection parallel with the axis of the drum.

9. A system for steering the casting belt in a continuous castingmachine of the revolving drum and belt type as claimed in claim 8 inwhich said flangeless pulley wheel mounted on said pivoted stand portionis the exit pulley wheel of the casting machine.

10. A system for steering the casting belt in a continuous castingmachine of the revolving drum and belt type as claimed in claim 7 inwhich the casting belt is a metal belt having a thickness ofless than0.060 of an inch.

